1. Field of the Invention
The invention is directed to the construction of a corrosion-resistant tension member in an area where it enters a structure, particularly an inclined cable at a pylon of a cable-stayed bridge.
2. Description of the Background Art
It is known with cable stayed bridges to load-transmittingly connect inclined cables with a pylon, with the inclined cables extending at an angle to one another and with which the roadway pillar is stayed against the pylon and which are primarily comprised of a bundle of individual elements, for example, steel wire strands. This for one can be accomplished with the stays coming from different directions all converging to the pylon there to be anchored, at times in a crisscross fashion; this requires a plurality of anchoring devices. Another option is to run the stays over the pylon in a saddle-like fashion, whereby the load-bearing forces extending at a right angle to the stay cable axis are transferred via the saddle to the pylon.
If such an inclined cable is damaged, for example, by the presence of corrosion on the steel tension members, it must be possible to replace such an inclined cable. In a conventional solution, a saddle-shaped canal is formed in the pylon for this purpose, into each of which one inclined cable can be inserted (DE 88 10 423 U). The lower area of the canal is comprised of a half tube forming a support trough with a saddle bearing at the vertex, where a saddle pipe sheathing the bundle of individual tension members in this area can be locked into place to avoid longitudinal offset. This is done with a bearing sleeve that is arranged in the vertex of the reversing point along the support trough, which is fitted with a bearing ring that is attached to the saddle pipe.
For stabilization purposes and to bond the individual tension members of the bundle with the saddle pipe, the remaining interstices are filled with a hardening material, for example, cement mortar. To improve the adhesion to the hardening material, the tension members, that is, for example, the steel wire strands, can preferably be roughened by sandblasting, at least in the area of the vertex.
In the conventional solution, the saddle pipe is directly connected with the sheathing of the bundle in the open area of the inclined cable outside the pylon by flange rings. As a result, the canal formed in the pylon, which must have a relatively large diameter, at least a greater height than the diameter of the bundle to make it possible to replace the bundle with the saddle pipe, is open on the front entry and/or exit point of the inclined cable. This opening is a disadvantage, because it is exposed to environmental influences and accessible to animals, particularly birds, which can cause dirt buildups and corrosion.